Nitrogen sources for neotropical nasute termites: Fixation and selective foraging.

Studies with Nasutitermes and Rhynchotermes (Isoptera, Nasutitermitinae) in a Costa Rican rainforest suggest that nitrogen fixation by gut symbionts may play a significant role in termite nutrition. Leaf-litter feeders ingest more and fix less nitrogen than do wood-litter feeders; both species feed preferentially on N-rich foods in their foraging repertoire. Unusually high N fixation (acetylene reduction) rates were found in Nasutitermes soldiers, thereby reducing their nutritional dependence on workers. Finally, N fixation rates of termites diminished rapidly within 24 h after removal of a colony from the field, underlining the importance of conducting future N fixation studies under field conditions.